Flexible guide pipe for underwater drilling



Nov. 3, 1970 J. DELACOUR ETA!- 3,538,238

FLEXIBLE GUIDE'PIPE FOR UNDERWATER DRILLING Filed June 28, 1968 2 Sheets-Sheet 1 6 v 9 4 pP/OQ Aer 5 v Fig.2

INVENTORS: 1060053 084196001? 5 REN/ REM/0A0 BY film 4 cmw'mw ATTORNEYS FLEXIBLE GUIDE PIPE FOR UNDERWATER DRILLING Filed June 28, 1968 Nov. 3, 1970 J. DELACOUR ETAL 2 Sheets-Sheet 2 INVENTOR M mm RA E 0M ms R ATTORNEYS United States Patent 3,538,238 FLEXIBLE GUIDE PIPE FOR UNDERWATER DRILLING Jacques Delacour, Paris, Remi Reynard, Montessori, and Michel Chatard, Chatou, France, assignors to Institut Francais du Petrole des Carburants et Lubrifiants, Rueil-Malmaison, Hauts-de-Seine, France Filed June 28, 1968, Ser. No. 741,138 Claims priority, application France, June 29, 1967,

11 Int. Cl. H01b 7 /00; E21b 7/12 U.S. Cl. 174-47 7 Claims ABSTRACT OF THE DISCLOSURE A flexible pipe permanently connects a submerged well head with a surface installation and is used both for guiding the lowering of the drill bit and for conveying the flushing fluid. This pipe which may include conductors for remote control is constituted by the combination of an internal armoring formed by the helical winding of a strip with interlocking convolutions and of an external sleeve tightly surrounding this armoring.

The present invention relates to a flexible guide pipe for underwater drilling from a surfaceinstallation, such as a ship or a drilling platform.

The object of this invention is to provide a flexible pipe for permanently connecting the surface installation with the underwater well head, this pipe being adapted to perform by itself several functions, comprising the guiding of the drill bit so as to permit the reintroduction thereof into the well, the circulation of the drilling or flushing fluid and optionally the remote control of the well head mechanisms and the transmission of data between the well head and the surface installation.

The invention provides a special pipe structure adapted to fulfill the above-indicated requirements, this special structure providing the pipe both with a great flexibility, allowing it to conform to the movements of the surface installation and with a high resistance to traction stresses, and also providing this pipe with an excellent resistance to abrasion, internally as well as externally.

In this pipe will advantageously be embedded electric wires and/ or flexible hydraulic hoses for transmitting control signals, data or power between the surface installation and the well head.

According to the invention a particular structure of flexible pipe permitting the achievement of these objects is constituted by the combination of an internal flexible metallic armoring resistant to abrasion, formed by the helical winding of a metallic strip forming interlocking convolutions provided with means for hydraulic sealing, and of an external sleeve or sock constituted by a winding or netting of metallic wires or cables tightly surrounding said metallic armoring, the pipe also including a lower hydraulic connecting element and an upper hydraulic connecting element, said elements providing for water-tight connections with the well head and the surface installation respectively for the circulation of drilling fluid through said pipe, said internal element being tightly secured at both of its ends to said connecting elements, said connecting elements being further provided with anchoring means for the respective ends of said external sleeve.

Under these conditions, the tractive stresses applied to the pipe result, on the one hand, in a constriction of the external sleeve on the internal armoring, which increases the coeflicient of friction of the metallic convolutions of this armoring on one another and, on the other hand, in a blocking of this constriction of the external sleeve or Patented Nov. 3, 1970 sock by the armoring, thereby limiting the elongation of this external sleeve and providing the pipe according to the invention with a good resistance to tractive stresses.

Some of the metallic wires or cables of the external sleeve may advantageously be electrically insulated so as to be used for transmitting control signals or measurements between the surface installation and the well head.

Small diametered hoses for hydraulic remote control may also be embedded in the external sleeve of the pipe.

An embodiment of the invention is described hereinunder, with reference to the attached drawings wherein:

FIG. 1 diagrammatically illustrates a conventional device for underwater drilling,

FIG. 2 illustrates an embodiment of the invention,

FIGS. 2A and 2B are detail views showing, on a larger scale, two embodiments of the internal armoring and of the means for making it watertight,

FIG. 3 is a view on a larger scale of the pipe shown by FIG. 2.

In FIG. 1 which diagrammatically shows a conventional equipment for underwater drilling, the reference numeral 1 designates a surface installation, 2 refers to the head of the drilled well and 3 indicates guide cables.

Two guide means 4, 5 of conventional design including radial arms slidable along the guide cables, allow to position successive elements, the aggregate of which constitutes the well head and which are provided with bores forming an axial passage for the drill stem or tubing.

This aggregate includes at its upper end means such as a stuffing box 6 providing for tightness in the annular space between the drill pipe and the wall of the axial bore of the well head, the return of the drilling mud to the surface installation occurring through the pipe 7.

The introduction into this bore of the drill stem or drill tubing provided at its lower end with a drill bit is performed by using the guide cables 3 and the guide means 4 and 5.

In FIG. 1, the reference numeral 8 designates a cable including conductors for remote measuring, transmitting to the surface installation data emanating from the well head.

The remote control from this surface installation of the devices, especially the valves, of the well head is performed by means of a line 9 for electric or hydraulic control.

The flexible guide pipe 10 according to the invention shown by FIG. 2 and, on a larger scale, by FIG. 3 (the same reference numerals have been used on these two figures to designate corresponding elements) is tightly connected at its lower part by a flange 11 with an hydraulic connector 12, which may be of a conventional design, located at the top of the well head 2 and, at its upper part, is tightly connected by a flange 13 with a hydraulic connector '14 connected by the pipe 15 with a circuit for recirculating the drilling mud (not shown).

This pipe includes an internal armoring 16 formed by the helical winding of a metallic strip with interlocking convolutions, having for example a S- or Z-shaped section which may be of a known type, this armoring having an internal diammeter which is suflicient to provide a passage for the drill bit and of the elements of the drill stem or drill tubing surmounting this drill bit.

In a first embodiment of this armoring 16 a detailed view of which is shown by FIG. 2A, the cross section of the metallic strip has the shape of a very flattened S, and a coating 17 of elastomeric or thermoplastic material provides for hydraulic sealing.

In another embodiment illustrated by FIG. 2B, the metallic strip 16a constituting the armoring has a substantially Z-shaped cross section including on each upper loop of the Z a housing for an helical sealing joint 17a.

The Armoring 16, 16a (FIG. 3) is flexible and must be 3 capable of withstanding the internal wear caused by the friction of the drill bit and of the assembly of the elements of the drill stem or drill tubing lowered and raised through the guide pipe according to the invention.

In order to provide the pipe with a sufficient resistance against the longitudinal tractive stresses applied thereto and resulting in particular from the own weight of this pipe and from the underwater currents, the pipe 10 includes, in combination with its internal metallic armoring 16, 16a an external sleeve or sock 18 formed of a winding or of a netting of metallic wires or cables clamping the internal armoring.

The wires or cables constituting this sleeve are at both their ends joined together so as to form connecting strands anchored on the adjacent connecting flange (flanges 11 and 13), being in the illustrated embodiment folded around anchoring pulleys 19 and 20, the axes of which are respectively integral with the lower flange 11 and the upper flange 13-, so as to constitute two knots 21 and 22.

Under these conditions any tractive force resulting in a compression of the internal armoring 16, 16a by the external sleeve 18, increases the mutual friction of the adjacent convolutions of this internal armoring on the one hand and, on the other hand, causes a constriction of the sleeve 18 around the internal armoring 16, 16a which blocks the sleeve 18 and thereby limits the axial elongation thereof.

This combination of the sleeve 18 and of the internal armoring 16, 16a thus provides the flexible pipe according to the invention with a resistance to tractive stresses which is suificient in the contemplated application.

Electrical conductors will advantageously be embedded in the sleeve or sock 18 so as to provide for the transmission of measurements between the well head and the surface installation, as well as, electric power conductors or pipes for the hydraulic control of the mechanisms, particularly of the valves of the well head from the surface installation.

The conductors may be constituted by some of the wires or cables of the sleeve 18, coated with an electrically insulating material, such as a polyamide.

The wires or cables of the sleeve 18, such as 23 (shown in dotted line within this sleeve), which are used as electric conductors, are connected with means 24 and 25 for electric connection with the well head and the electric equipment of the surface installation respectively.

The armoring 16, 16a will advantageously be precompressed in the axial direction so as to, on the one l 1and, reduce the spacing between its convolutions thereby reducing the risks of jamming of the teeth of the drill bit therebetween, and, on the other hand, increase the resistance of this armoring to crushing, this resistance being necessary for withstanding the crushing stresses applied by the sleeve 18 when the whole pipe is subjected to a tractive force.

In order to completely eliminate these risks of jamming it will be possible, as illustrated by FIG. 2B, to place an intermediary metallic strip 26 between the ad acent convolutions of the metallic strip 16a which constitutes the armoring during the operation of interlocking the convolutions of this last mentioned strip.

What is claimed is:

1. Flexible guide pipe for underwater drilling from a surface installation, said pipe being for permanently connecting a well head with said surface installation and capable of being used both for conveying the flushing fluid and for guiding the lowering of the drill bit so as to introduce said bit into the drilled well, wherein said pipe includes in combination an internal metallic armoring withstanding abrasion and constituted by the helical winding of a metallic strip with interlocking convolutions, provided with means for hydraulic sealing, and an external sleeve made of a netting of metallic wires tightly surrounding said metallic armoring, a lower hydraulic connecting element and an upper hydraulic connecting element adapted to provide connection with the Well head and the surface installation respectively, said internal armoring being tightly secured to said connecting elements at its upper and lower ends respectively, means anchoring folded ends of the wires of said external sleeve on said two connecting elements respectively, so that a tractive force applied to the pipe results in said sleeve being constricted on said internal armoring, thereby limiting on the one hand the lengthening of the armoring by increasing the coefficient of mutual friction of the adjacent convolutions of this armoring, as a result of the constriction of said sleeve and, on the other hand, blocking said constriction of said sleeve by said armoring, thereby also limiting the elongation of said sleeve.

2. Flexible pipe in accordance with claim 1, wherein at least some of the metallic wires of the external sleeve are electrically insulated and are used as electrical conductors for the transmission of control or data signals between the surface installation and the well head.

3. Flexible pipe in accordance with claim 1, wherein hoses for hydraulic remote control are embedded in said external sleeve.

4. Flexible pipe in accordance with claim 1, wherein an intermediary metallic strip is inserted between the adjacent convolutions of the strip constituting the internal armoring, so as to suppress the risks of jamming of the drill bit between said convolutions.

5. Flexible guide pipe for connecting a well head to a surface installation including in combination an internal metallic armoring constituted by the helical winding of a metallic strip with interlocking convolutions and an external sleeve made of a netting of metallic wires tightly surrounding said metallic armoring, a lower hydraulic connecting element and an upper hydraulic connecting element adapted to provide connection with the well head and the surface installation respectively, means anchoring folded ends of the wires of said external sleeve on said two connecting elements respectively, so that a tractive force applied to the pipe results in said sleeve being constricted on said internal armoring, thereby limiting, on the=one hand, the lengthening of the armoring by increasing the coeflicient of mutual friction of the adjacent convolutions of this armoring, as a result of the constriction of said sleeve and, on the other hand, blocking said constriction of said sleeve by said armoring, thereby also limiting the elongation of said sleeve.

6. Flexible guide pipe for connecting a well head to a surface installation including in combination an internal armoring constituted by the helical winding of a metallic strip with interlocking convolutions, provided with means for hydraulic sealing, and an external sleeve made of a netting of metallic wires tightly surrounding said metallic armoring, a lower hydraulic connecting element and an upper hydraulic connecting element adapted to provide connection with the well head and the surface installation respectively, said internal armoring being tightly secured to said connecting elements at its upper and lower ends respectively, said metallic wires of said external sleeve being joined together at each end of said sleeve so as to form at least one connecting strand, means anchoring said strands on said two connecting elements respectively, so that atractive force applied to the pipe results in said sleeve being constructed on said internal armoring, thereby limiting, on the one hand, the lengthening of the armoring by increasing the coeflicient of mutual friction of the adjacent convolutions of this armoring, as a result of the constriction of said sleeve and, on the other hand, blocking said construction of said sleeve by said armoring, thereby also limiting the elongation of said sleeve.

5 6 7. Flexible pipe in accordance with claim 6, wherein 2,028,793 1/1936 Mascuch 174106 X said anchoring means include anchoring pulleys over 2,402,503 6/1946 McCutchan 174-35.1 X which said strands are folded. 2,409,530 10/ 1946 Bennett 174109 X 2,43 8,146 3/ 1948 Candee et al.

FOREIGN PATENTS 1,069,274 5/ 1967 Great Britain.

References Cited UNITED STATES PATENTS 330,910 11/1885 Levavasseur.

973,901 1-0/1910 Witzenmann 133 110 X LARAMIE E-ASKINPrimary Examiner 1,023,032 4/1912 Pechstein 138---135 Us cl XR 1,198,392 9/1916 Brinkman 174 109 10 1,365,306 1/19211 Dickinson. 138110, 136; 166-.6; 17470, 109; 1757 

